Unless otherwise configured, the client libraries useApplication Default Credentialsto authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing theUnifiedCredentialsOptionThe following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::notebooks_v1::ManagedNotebookServiceClient(
google::cloud::notebooks_v1::MakeManagedNotebookServiceConnection(
options));
}
Follow these links to find examples for other*Clientclasses:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on how to utilize a service account key file for authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation covers multiple versions of the client library, from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eIt demonstrates how to override authentication by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e to load a service account key file, illustrated with a code example.\u003c/p\u003e\n"],["\u003cp\u003eExamples are available for various client classes, such as \u003ccode\u003enotebooks_v1::ManagedNotebookServiceClient\u003c/code\u003e, \u003ccode\u003enotebooks_v1::NotebookServiceClient\u003c/code\u003e, and \u003ccode\u003enotebooks_v2::NotebookServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eUsers are encouraged to follow best practices for service account key management, and there is a link to the "Best practices for managing service account keys" guide for more details, as well as link to Authentication Components.\u003c/p\u003e\n"]]],[],null,["Version 2.18.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/notebooks/latest/notebooks-override-authentication)\n- [2.41.0](/cpp/docs/reference/notebooks/2.41.0/notebooks-override-authentication)\n- [2.40.0](/cpp/docs/reference/notebooks/2.40.0/notebooks-override-authentication)\n- [2.39.0](/cpp/docs/reference/notebooks/2.39.0/notebooks-override-authentication)\n- [2.38.0](/cpp/docs/reference/notebooks/2.38.0/notebooks-override-authentication)\n- [2.37.0](/cpp/docs/reference/notebooks/2.37.0/notebooks-override-authentication)\n- [2.36.0](/cpp/docs/reference/notebooks/2.36.0/notebooks-override-authentication)\n- [2.35.0](/cpp/docs/reference/notebooks/2.35.0/notebooks-override-authentication)\n- [2.34.0](/cpp/docs/reference/notebooks/2.34.0/notebooks-override-authentication)\n- [2.33.0](/cpp/docs/reference/notebooks/2.33.0/notebooks-override-authentication)\n- [2.32.0](/cpp/docs/reference/notebooks/2.32.0/notebooks-override-authentication)\n- [2.31.0](/cpp/docs/reference/notebooks/2.31.0/notebooks-override-authentication)\n- [2.30.0](/cpp/docs/reference/notebooks/2.30.0/notebooks-override-authentication)\n- [2.29.0](/cpp/docs/reference/notebooks/2.29.0/notebooks-override-authentication)\n- [2.28.0](/cpp/docs/reference/notebooks/2.28.0/notebooks-override-authentication)\n- [2.27.0](/cpp/docs/reference/notebooks/2.27.0/notebooks-override-authentication)\n- [2.26.0](/cpp/docs/reference/notebooks/2.26.0/notebooks-override-authentication)\n- [2.25.1](/cpp/docs/reference/notebooks/2.25.1/notebooks-override-authentication)\n- [2.24.0](/cpp/docs/reference/notebooks/2.24.0/notebooks-override-authentication)\n- [2.23.0](/cpp/docs/reference/notebooks/2.23.0/notebooks-override-authentication)\n- [2.22.1](/cpp/docs/reference/notebooks/2.22.1/notebooks-override-authentication)\n- [2.21.0](/cpp/docs/reference/notebooks/2.21.0/notebooks-override-authentication)\n- [2.20.0](/cpp/docs/reference/notebooks/2.20.0/notebooks-override-authentication)\n- [2.19.0](/cpp/docs/reference/notebooks/2.19.0/notebooks-override-authentication)\n- [2.18.0](/cpp/docs/reference/notebooks/2.18.0/notebooks-override-authentication)\n- [2.17.0](/cpp/docs/reference/notebooks/2.17.0/notebooks-override-authentication)\n- [2.16.0](/cpp/docs/reference/notebooks/2.16.0/notebooks-override-authentication)\n- [2.15.1](/cpp/docs/reference/notebooks/2.15.1/notebooks-override-authentication)\n- [2.14.0](/cpp/docs/reference/notebooks/2.14.0/notebooks-override-authentication)\n- [2.13.0](/cpp/docs/reference/notebooks/2.13.0/notebooks-override-authentication)\n- [2.12.0](/cpp/docs/reference/notebooks/2.12.0/notebooks-override-authentication)\n- [2.11.0](/cpp/docs/reference/notebooks/2.11.0/notebooks-override-authentication) \n\nHow to Override the Authentication Credentials\n==============================================\n\nUnless otherwise configured, the client libraries use [Application Default Credentials](https://cloud.google.com/docs/authentication#adc) to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the [UnifiedCredentialsOption](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1UnifiedCredentialsOption.html) The following example shows how to explicitly load a service account key file: \n\n [](std::string const& keyfile) {\n auto is = std::ifstream(keyfile);\n is.exceptions(std::ios::badbit); // Minimal error handling in examples\n auto contents = std::string(std::istreambuf_iterator\u003cchar\u003e(is.rdbuf()), {});\n auto options =\n google::cloud::Options{}.set\u003cgoogle::cloud::UnifiedCredentialsOption\u003e(\n google::cloud::MakeServiceAccountCredentials(contents));\n return google::cloud::notebooks_v1::ManagedNotebookServiceClient(\n google::cloud::notebooks_v1::MakeManagedNotebookServiceConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`notebooks_v1::ManagedNotebookServiceClient`](/cpp/docs/reference/notebooks/2.18.0/notebooks_v1_1_1ManagedNotebookServiceClient-service-account-snippet)\n- [`notebooks_v1::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.18.0/notebooks_v1_1_1NotebookServiceClient-service-account-snippet)\n- [`notebooks_v2::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.18.0/notebooks_v2_1_1NotebookServiceClient-service-account-snippet)\n\nKeep in mind that we chose this as an example because it is relatively easy to understand. Consult the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys) guide for more details.\n\n###### See Also\n\n[Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) - for more information on the factory functions to create [`google::cloud::Credentials`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1Credentials.html) objects."]]